Hetero phase polymer compositions

ABSTRACT

Hetero phase polymer compositions are described. The compositions may have polypropylene component, a modifier component and a compatibilizer component. The modifier component may in some embodiments be an ethylene α-olefin copolymer with a density ≧0.905 g/cm 3 . In other embodiments the modifier component may be a blend of a copolymer with a density of ≧0.905 g/cm 3 , and an ethylene α-olefin copolymer of lower, more traditional density.

RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 10/688,091, filed Oct. 17, 2003, which claims the benefit ofU.S. Provisional Application No. 60/419,183, filed Oct. 17, 2002, theentire disclosure of which is hereby incorporated by reference.

FIELD

The invention relates to hetero phase compositions, such asthermoplastic olefin (TPO) compositions, for use, among other uses, inthe manufacture of automotive components, and for use in articles madefrom such compositions.

BACKGROUND

Embodiments of our invention relate to hetero phase polymer compositionshaving three main polymeric components comprising a polypropylenecomponent, a modifier component and a compatibilizer component. Thecompatibilizer component imparts a greater degree of compatibilitybetween the polypropylene component and modifier component phases,yielding improved physical properties, notably impact strength.Non-polymeric components may also be present in the compositions.

The term hetero phase polymer compositions refers to the presence of atleast two phases: a continuous or matrix phase and a discontinuous ordisperse phase distributed within the matrix phase.

Hetero phase polymer compositions include compositions generallyreferred to as Thermoplastic Olefin (TPO) Compositions, which are blendsof polypropylene, modifier and optionally non-polymeric components suchas fillers and other compounding ingredients. TPOs are multiphasepolymer blends where the polypropylene forms a continuous matrix phaseand the modifier component, generally derived from an ethylenecontaining interpolymer, is the dispersed component. The polypropylenematrix imparts tensile strength and chemical resistance to the TPO,while the ethylene polymer imparts flexibility and impact resistance.Generally speaking, TPOs have a dispersed phase which is not, or onlymodestly, cross-linked.

Hetero phase polymer compositions also include compositions generallyreferred to as thermoplastic vulcanizates (TPVs), which are also blendsof polypropylene, modifier and optionally non-polymeric components suchas fillers and other compounding ingredients, with the exception thatthermoplastic vulcanizates are multiphase polymer blends where thedispersed modifier component is cross-linked or “vulcanized” to providea rubber-like resilience to the composition.

Traditionally, highly amorphous, very low density ethylene-propylenecopolymers (EP) and ethylene-propylene-diene terpolymers (EPDM) havebeen used as the modifier component in hetero phase compositions, theseEP or EPDMs generally have a high molecular weight expressed in Mooneyunits. Recently, other ethylene-alpha olefin copolymers have been used,especially very low density ethylene-butene, ethylene-hexene andethylene-octene copolymers which generally have a lower molecular weightexpressed in Melt Index units. The density of these latter polymers isgenerally less than 0.900 g/cm3, indicative of some residualcrystallinity in the polymer. The major market for TPOs is in themanufacture of automotive parts, especially bumper fascia. Otherapplications include automotive interior components such as door skin,air bag cover, side pillars and the like. These parts are generally madeusing an injection molding processes. To increase efficiency and reducecosts it is necessary to decrease molding times and reduce wallthickness in the molds. To accomplish these goals, manufacturers haveturned to high melt flow polypropylenes (Melt Flow Rate >35 g/10 min.).These high melt flow rate (MFR) resins are low in molecular weight andconsequently difficult to toughen, resulting in products that have lowimpact strength.

U.S. Pat. No. 6,245,856 suggests hetero phase compositions of the TPOtype containing a polypropylene component, modifier component andcompatibilizer component. The polypropylene component is generallydescribed as a polypropylene homopolymer having a relatively high MFR.This document refers to the possible use of polypropylene impactcopolymers without restricting the nature and amount of the othercomponents. The modifier component is described as an elastomercomponent which can be an ethylene alpha olefin copolymer or an ethylenealpha olefin diene terpolymer. The density of the modifier component isstated to range from 0.85 to 0.90 g/cm3.

There is a need therefore for TPO manufacturers to be able to broadenthe scope of polymers available to manufacture end use items with abetter balance between the performance of the hetero phase compositionin its end use, the processability during conversion of the moltencompositions into the end use article and the cost of providing thoseproperties.

Other background references include U.S. Pat. No. 5,959,030 to Berta,U.S. Pat. No. 6,245,856 to Kaufman et al., U.S. Pat. No. 6,232,402 toDemeuse, WO 97/20888, and EP 0 792 914.

SUMMARY

We have discovered that by employing the compatibilizer componentdisclosed herein, it is possible to use modifier components of increaseddensity and crystallinity, often being less resilient than materialswhich heretofore have not been considered suitable for impactmodification of TPOs. The density of the modifier component overall maybe raised in some embodiments to a level where it exceeds the densityhitherto assumed to be desirable for impact modification, where totallyamorphous impact modifiers were preferred.

In a first aspect of the invention there is provided a hetero phasepolymeric composition, comprising:

-   -   a) a polypropylene component, present in said hetero phase        polymer composition as a continuous phase, said polypropylene        component having a melting point Tm≧110° C.;    -   b) a modifier component, said modifier component being a        dispersed phase in said hetero phase polymer composition, said        modifier component comprising at least 10 percent by weight of        the total modifier component being an ethylene α-olefin polymer        having a density ≧0.905 g/cm³;    -   c) a compatibilizer component, present in said hetero phase        polymer composition in a compatibilizing amount, said        compatibilizer component having a Δ Hf<45 J/g, said        compatibilizer component having propylene sequences        co-crystallizable with the polypropylene component of a).

In another aspect of the invention there is provided a hetero phasepolymer composition, comprising:

-   -   a) a polypropylene (polypropylene component) having        polypropylene crystallinity, due to the presence of one of        isotactic or syndiotactic sequences in said polypropylene;    -   b) an ethylene α-olefin polymer being substantially free from        propylene crystallinity, having a density of ≧0.905 g/cm³; and    -   c) polymer compatibilizer having propylene crystallinity        substantially the same as that in a).

In a further aspect of our invention we describe a two phase polymerblend comprising:

-   -   a) a polypropylene component (PPC) present as a continuous        phase, the polypropylene component having a Tm>110° C. or a Δ        Hf>60 J/g, and wherein the polypropylene component has        crystallinity from one of isotactic or syndiotactic sequences;    -   b) a modifier component (MC), present in the polymer blend at        ≦10 weight percent, based on the total polymer weight of the        blend, the modifier component having a density in the range of        from 0.85–0.965 g/cm³; and    -   c) a polymer compatibilizer (CC), present in the blend at a        compatibilizing amount, the compatibilizer component having a Δ        Hf<45 J/g, said compatibilizer component having propylene        sequences that co-crystallize with the polypropylene component        of a).

In a further aspect of our invention, a two phase polymer composition isprovided, comprising:

-   -   a) an impact copolymer of propylene (ICP), the ICP having one or        more of Tm>140° C., Δ Hf>95J/g, or an α-olefin content of one        of >2 or <25 weight percent, a molecular weight in the range of        from 10,000–5,000,000, a melt flow rate in the range of from        15–60, the ICP present in the two phase polymer composition in        the range of from 70–90 weight percent;    -   b) an ethylene α-olefin copolymer, wherein the α-olefin is one        or more of butene-1, hexene-1, or octene-1, the ethylene        copolymer having a density ≧0.905 g/cm³, the ethylene copolymer        may be a blend of two or more ethylene α-olefin copolymers, and        if a blend, the aggregate density is ≧0.905 g/cm³, the ethylene        α-olefin copolymer being present in the two phase polymer        composition in the range of from 15–22 weight percent, having an        melt index in the range of from 0.1–10 g/10 minutes;    -   c) a compatibilizer component present in the two phase polymer        composition in the range of 0.1–8 weight percent, the        compatibilizer component is a polymer of propylene and one or        more of ethylene, butene-1, hexene-1, or octene-1, the        compatibilizer component has a crystallinity defined by one of        Tm<100° C., or a Δ Hf<25 J/g, wherein the compatibilizer        component has a narrow compositional distribution, such that >75        wt. % of the compatibilizer component may be isolated in a        thermal fractionation, in 2 adjacent soluble fractions, where        each fraction differs <20% from the average weight present        α-olefin of the total compatibilizer component.

In another aspect of our invention a hetero phase polymeric compositionis contemplated, comprising:

-   -   a) a polypropylene component present in the hetero phase polymer        composition as a continuous phase, the PP having a melting point        Tm≧100° C.;    -   b) a modifier component, the modifier component being a        dispersed phase in the hetero phase polymer composition, said        modifier component comprising at least 10% by weight of the        total modifier component of a polymer derived from ethylene and        an alpha-olefin having from 4 to 20 carbon atoms with a density        of at least 0.88 g/cm³ and crystallinity sufficient for        determination of the CDBI with a CDBI of at least 50%;    -   c) a compatibilizing amount of a compatibilizer component,        derived to an extent of at least 50 mole % of propylene        compatibilizer component and having a Δ Hf<45 J/g which is        co-crystallizable with the polypropylene component.

In another aspect, a two phase polymer composition is contemplated,comprising:

-   -   a) an impact copolymer of propylene (ICP), said ICP having one        or more of Tm>140° C., Δ Hf>95J/g, or an α-olefin content of one        of >2 or <25 weight percent, a molecular weight in the range of        from 10,000–5,000,000, a melt flow rate in the range of from        15–60 dg/min., the ICP present in said two phase polymer        composition in the range of from 70–90 weight percent;    -   b) an ethylene α-olefin copolymer, wherein the α-olefin is one        or more of butene-1, hexene-1, or octene-1, said ethylene        copolymer having a density ≧0.905 g/cm³, the ethylene copolymer        may be a blend of two or more ethylene α-olefin copolymers, and        if a blend, the aggregate density is ≧0.905 g/cm³, the ethylene        α-olefin copolymer being present in said two phase polymer        composition in the range of from 15–22 weight percent, having an        melt index in the range of from 0.1–10 g/10 minutes;    -   c) a compatibilizer component (CC) present in the two phase        polymer composition in the range of 0.1–8 weight percent, the        compatibilizer component is a polymer of propylene and one or        more of ethylene, butene-1, hexene-1, or octene-1, the        compatibilizer component has a crystallinity defined by one of        Tm<100° C., or a Δ Hf<25 J/g, wherein the compatibilizer        component has a narrow compositional distribution, such that >75        wt. % of the compatibilizer component may be isolated in a        thermal fractionation, in 2 adjacent soluble fractions, where        each fraction differs <20% from the average weight present        α-olefin of the total compatibilizer component.

The hetero phase polymer compositions of embodiments of our inventionmay be prepared by blending the polypropylene component with themodifier component and a compatibilizer component.

These and other features, aspects and advantages of embodiments of ourinvention will become better understood with reference to the followingdescription, and appended claims.

DESCRIPTION

We contemplate hetero phase polymer compositions composed of apolypropylene component, a modifier component and a compatibilizercomponent.

The Modifier Component

The modifier component may be comprised of one or more ethylene-alphaolefin copolymers and have an aggregate density above 0.900 g/cm3, or inanother embodiment ≧10 weight percent of the modifier component may bean ethylene alpha-olefin polymer having a density above 0.900 g/cm3.

Alternatively, ≧10 percent by weight of the total weight of the modifiercomponent, is a copolymer with a density of ≧0.905 g/cm3or ≧0.910g/cm3or ≧0.912 g/cm3. This polymer may form ≧20, or ≧30, or ≧40, or ≧50,or >60, or ≧70, or ≧80, or ≧90 of the total of the modifier component ona weight percent basis. Or this copolymer may constitute substantiallythe whole of the modifier component. If two or more ethylene α-olefinpolymers are combined to form the modifier component, they may be thesame or different in their selection of comonomers and/or the amount ofcomonomer or comonomer amounts and/or densities.

The added polymer (one differing in density and or amount or type ofcomonomer from the copolymer described above) may be one generally usedconventionally as modifier in TPOs, and as such may be generally lowerin density than the first polymer described above. The amounts of suchadded or second polymer depend on the balance of effects desired.Generally a lower density polymer may enhance properties such as impactstrength, while a higher density polymer, owing to its highercrystallinity, may enhance stiffness and tensile strength in the TPOcompound. This additional polymer or polymers may be present in themodifier component at ≦80, or ≦70, or ≦60, or ≦50, or ≦40, or ≦30, or≦20, or ≦10 weight percent. Such polymers of lower density include, butare not limited to polymers of having a density of ≦0.900, or ≦0.895, or≦0.890, or ≦0.885, and/or ≧0.860, or ≧0.865 g/cm3

The modifier component (either a single polymer or blends) may bepresent in the hetero phase polymer composition as a disperse phase, ina continuous phase of the polypropylene component. Thus, the amount ofmodifier component should not exceed that needed to maintain itsdispersed condition in the polypropylene component continuous phase.When such an upper limit is reached, (the upper boundary of maintaininga dispersed condition) additional amounts of modifier component willtend to result in the modifier becoming a so-called “co-continuousphase” in which discrete, dispersed phase islands will coalesce intolarger islands. This co-continuous state may be detrimental to physicalproperties, as the flexural modulus is lowered. To mitigate sucheffects, if larger amounts of modifier component are desired orrequired, a full or partial cross-linking can be effected. This full orpartial cross-linking may decrease the tendency to co-continuity. Suchcross-linking can be effected by chemical means (peroxide or sulfur orsilane, azides, etc.) or by non-chemical means such as electron beamradiation.

The sizes of the individual domains of the dispersed phase are generallysmall, with the smallest length dimension for the dispersed phase beingless than 10 μm. This phase size of the dispersed phase may bemaintained during processing even without crosslinking. The dispersephase is comprised of a mixture of the modifier component with someamount of the polypropylene component, due to thermodynamic mixing ofpolymers. The balance of the polymers not in this disperse phase make upthe continuous phase.

The one or more copolymers that make up the modifier component may besubstantially free of propylene crystallinity, by which we intend <10 or<5 or <1 or 0 percent of propylene crystallinity is in the modifiercomponent as determined by Differential Scanning Calorimetry (DSC).

The one or more ethylene α-olefin copolymers that make up the modifiercomponent may include C3 to C20 alpha olefin derived units. Or the C4 toC10 alpha olefin derived units, for example, butene-1, hexene-1 oroctene-1, and optionally the copolymers may contain diene derived units.Such combinations of ethylene and α-olefins as described above include,but are not limited to, copolymers such as ethylene-propylene;ethylene-butene-1; ethylene-hexene-1; ethylene-pentene-1;ethylene-4-methyl-1-pentene; ethylene-octene-1;ethylene-propylene-butene-1; ethylene-propylene-hexene-1;ethylene-propylene-pentene-1; ethylene-propylene-octene-1; and the likemay be used as the polyethylene portion of the hetero phase polymercomposition.

The one or more α-olefin derived units may be present in the ethylenecopolymer in an amount of less than 30 mole percent based on thecopolymer, or less than 25 mole percent, or less than 20 mole percent.If the optional diene is present, it may range from ≧0.5 to ≦10 weightpercent, or from ≧0.5 to ≦7 weight percent (based on FTIRdetermination). The ethylene content of the copolymer may generallyrange from 60–100 weight percent, or at least 70 and/or 95 weightpercent or less.

The copolymer generally may have a number average molecular weight, asdetermined by GPC, of from 30,000 to 500,000 or may be greater than50,000 and/or less than 100,000. The Melt Index may be from 0.1 to 20g/10 minutes.

The copolymer may have a CDBI of at least 50%, or at least 60% or even65% and a weight average molecular weight distribution of from 1.5–4 or1.7–3.5, or at least 1.8 and/or less than 3.0. This homogeneity andmolecular weight and compositional distribution, as indicated by theCDBI, reflects a reduction in the presence of lower molecular weight,higher comonomer content impurities. Such polymer can be produced usingmetallocene based catalyst systems in gas phase or solution processes.The metallocene based catalysts used for such polymerizations aregenerally of the metallocene-alumoxane, metallocene-ionizing activatortype. Useful catalysts are those disclosed in EP 129368, U.S. Pat. Nos.5,026,798 and 5,198,401 each incorporated herein by reference.

The copolymer may or may not contain long chain branches, whose presencemay be inferred from rheology-type measurements such as melt tension andthe internal energy of activation for melt flow.

The modifier component may comprise polymers derived from cyclicmono-olefins such as styrene and both linear and cyclic dienes can alsobe used. For a discussion of such dienes, U.S. Pat. No. 6,245,846 isincorporated by reference.

The modifier component can be linear, substantially linear, blocky orbranched. For a discussion of such options, U.S. Pat. No. 6,245,846 isincorporated by reference.

The Compatibilizer Component

The compatibilizer component may comprise an ethylene-propylenecopolymer having a propylene derived content of greater than 50 weightpercent. Optionally, ethylene can be replaced or added to such polymerswith a C4–C20 or C4–C12 α-olefin, such as, for example, one or more of1-butene, 4-methyl-1-pentene, 1-hexene or 1-octene or decene.

The propylene content may vary from 50 to 92 weight percent, or at least70 weight percent and/or less than 90 weight percent, or at least 75weight percent and/or less than 90 weight percent.

The compatibilizer component may be one of isotactic, atactic,syndiotactic or combinations thereof. The tacticity should be adapted toensure compatibility, especially relative to the polypropylenecomponent. In some embodiments of our invention, the tacticity of thepolypropylene component and the compatibilizer component may besubstantially the same, by substantially we intend that these twocomponents have at least 80, or 90, or 95, or 100% of the sametacticity. Even if the components are of mixed tacticity (i.e. partiallyisotactic and partially syndiotactic) the percentages in each should beat least 80% or greater the same as the other component.

The compatibilizer component may be co-crystallizable with thepolypropylene component. The co-crystallizablility may be tested bycomparing the DSC melting behavior before and after mixing samples ofthe polypropylene component and compatibilizer component. Asco-crystallization occurs, both the melting point and glass transitiontemperature of the blend will begin to fall. The co-crystallizationphenomenon can also be observed by studying the morphology at theinterface of the modifier and the polypropylene component usingTransmission Electron Microscopy (TEM). In a TEM view, inco-crystallized areas, either the compatibilizer component and/or thepolypropylene component may appear as a single phase in the blend, orthey may also appear as discrete phases with a high degree ofinterfacial and epitaxial crystallization between the polypropylenecomponent and the compatibilizer component.

Both the polypropylene component and the compatibilizer component mayhave isotactic sequences. The type of crystallinity, or lack thereof(isotactic, syndiotactic, atactic, ethylene) may be determined by NMR.For the compatibilizer component the presence of isotactic sequences canbe determined by NMR measurements showing two or more propylene derivedunits arranged isotactically. In the compatibilizer component, theisotactic sequences may be interrupted by units which are notisotactically arranged or by units that otherwise disturb thecrystallinity derived from the isotactic sequences. The crystallinity ofthe compatibilizer component may be from 2–65% or 5–40% of anidentically treated (any steps taken with one sample are takenidentically with the comparison sample, for example, annealing, and/orstresses introduced during fabrication and/or measurement) isotacticpolypropylene, as determined by DSC.

Thus, the compatibilizer component has a heat of fusion of less than 45J/g. The crystallinity interruption may be predominantly controlled bythe incorporation of monomer units other than propylene, such asethylene. In one embodiment, the compatibilizer component may be acopolymer including from a lower limit of 5%, or 6%, or 8%, or 10% byweight to an upper limit of 20%, or 25%, or 30%, or 35%, or 40% byweight ethylene-derived units, and from a lower limit of 60% or 70% byweight to an upper limit of 95%, or 94%, or 92%, or 90% by weightpropylene-derived units, the percentages by weight based on the totalweight of propylene- and ethylene-derived units. The copolymer mayoptionally contain diene-derived units.

The compatibilizer component may include some or all of the followingcharacteristics, where ranges from any recited upper limit to anyrecited lower limit are contemplated:

-   -   a) a melting point, generally a single melting point, ranging        from an upper limit of less than 110° C., or less than 105° C.        or less than 90° C., or less than 80° C., or less than 70° C.,        to a lower limit of greater than 25° C., or greater than 35° C.,        or greater than 40° C., or greater than 45° C.;    -   b) a heat of fusion ranging from a lower limit of greater than        1.0 joule per gram (J/g), or greater than 1.5 J/g, or greater        than 4.0 J/g, or greater than 6.0 J/g, or greater than 7.0 J/g,        to an upper limit of less than 45 J/g, or less than 40 J/g, or        less than 35 J/g, or less than 30 J/g, or less than 25 J/g, or        less than 20 J/g;    -   c) a molecular weight distribution (MWD) M_(w)/M_(n) ranging        from a lower limit of 1.5 or 1.8 to an upper limit of 40, or 20,        or 10, or 5, or 3;    -   d) a number average molecular weight of from 10,000–5,000,000 or        from 40,000–300,000 or from 80,000–200,000, as determined by gel        permeation chromatography (GPC); or    -   e) a Mooney viscosity ML (1+4)@125° C.<100 or <75.

In embodiments of our invention, at least 75% by weight, or at least 80%by weight, or at least 85% by weight, or at least 90% by weight, or atleast 95% by weight, or at least 97% by weight, or at least 99% byweight of the compatibilizer component may be soluble in a singletemperature fraction, or in two adjacent temperature fractions, with thebalance of the copolymer in immediately preceding or succeedingtemperature fractions. These percentages are fractions, for instance inhexane, beginning at 23° C. and the subsequent fractions are inapproximately 8° C. increments above 23° C. Meeting such a fractionationrequirement means that a polymer has statistically insignificantintermolecular differences in propylene tacticity.

Fractionations may be conducted in boiling pentane, hexane, heptane andeven di-ethyl ether. In such boiling solvent fractionations, polymersmaking up compatibilizing components of embodiments of our invention maybe totally soluble in each of the solvents, offering no analyticalinformation. For this reason, we have chosen to do the fractionation asreferred to above and as detailed herein, to find a point within thesetraditional fractionations to more fully describe our polymer and thesurprising and unexpected insignificant intermolecular differences oftacticity of the polymerized propylene.

The compatibilizer component polymers are generally devoid of anysubstantial intermolecular heterogeneity in tacticity and comonomercomposition. They are also substantially devoid of any substantialheterogeneity in intramolecular composition distribution. This istypical of metallocene catalyst produced polymers. Intramolecularheterogeneity is not intrinsic to metallocene polymers and can only beforced through composition sequencing during synthesis (e.g. seriesreactor).

The compatibilizer component has a crystalline portion and an amorphousportion, the amorphous portion being the result of one of stereo errorintroduced by a catalyst or by the amount and nature of a comonomer. Thecompatibilizer component is more fully discussed in US publishedapplication US 2002/0004575 A1.

The Polypropylene Component

The polypropylene component may have MFRs ranging from 15–100, or >15,or >20, or >25, or >30, or <100, or <90, or <80, or <70, or <60 dg/min.

The polypropylene component, may be a polymer having primarilyisotactic, syndiotactic, atactic or combinations of polypropylenecrystallinity.

The polypropylene component may have melting temperature (Tm) of >100°C., or >110° C., or >115° C., or >120° C., or >125° C., or >130° C.,or >130° C., as determined by ASTM D-3417.

The polypropylene component may have a heat of fusion (Δ Hf)>60, or >70,or >80, or >85, or >90, or >95 J/g (as determined also by DSC).Generally speaking, the crystallinity is a major influence on the heatof fusion and melting temperature, and should be higher for thepolypropylene component than that of the compatibilizer component.

The polypropylene component may have a number average molecular weight(Mn) in the range of from 10,000 to 5,000,000. And a melt flow rate(MFR) (determined by the ASTM D1238 technique, condition L) in the rangeof from 15 to 200 or >15 and/or <120 dg/min.

The polypropylene component may be a copolymer containing α-olefinderived units at generally <70, to >2, or <50, to >2, or <40, to >2, or<30, to >2, or <25 weight percent, based on the total weight of thepolypropylene component. Exemplary α-olefins are those α-olefins with 4to 12 carbon atoms and ethylene. For example, the α-olefin or α-olefinsmay be one or more of ethylene, butene-1,4 methyl-1-pentene, hexene-1,octene-1.

In one embodiment, the polypropylene component has a melting point above120° C. and is a random copolymer of propylene derived units and up to10 mol % ethylene and/or butene-1.

The polypropylene component may be a continuous phase in the heterophase polymer composition of embodiments of our invention. Thepolypropylene component and compatibilizer component discussed herein,may have substantially the same stereo regularity, selected fromisotactic, syndiotactic, atactic or combinations thereof.

The polypropylene component used in the practice of the invention can beprepared using any known technology for the production of polypropylene.This includes the use of traditional Ziegler-Natta catalyst systems aswell as metallocene catalyst systems.

Polypropylene Impact Copolymer (ICP)

In embodiments of our invention, when the polypropylene component is animpact copolymer, such ICPs are themselves two phase systems, however inthe present hetero phase blends, each of the two individual phases ofthe ICP may generally blend with the respective phase of the blend, i.e.crystalline and/or amorphous.

As indicated, an ICP can be in the polypropylene component as part orall of the PPC, used in combinations with the other components of thehetero phase composition. The ICPs have melt flow rates (MFR) of thepolypropylene homopolymer portion of the ICP (determined by the ASTMD1238 technique, condition L) in the range of from 15 to 200, or atleast 15 and/or less than 120 dg/min. Exemplary alpha-olefins for therubber portion of the ICP, may be selected from one or more of ethylene;and C4 to C20 alpha olefins such as butene-1;pentene-1,2-methylpentene-1,3-methylbutene-1;hexene-1,3-methylpentene-1,4-methylpentene-1,3,3-dimethylbutene-1;heptene-1; hexene-1; methylhexene-1; dimethylpentene-1trimethylbutene-1; ethylpentene-1; octene-1; methylpentene-1;dimethylhexene-1; trimethylpentene-1; ethylhexene-1;methylethylpentene-1; diethylbutene-1; propylpentane-1; decene-1;methylnonene-1; nonene-1; dimethyloctene-1; trimethylheptene-1;ethyloctene-1; methylethylbutene-1; diethylhexene-1; dodecene-1 andhexadodecene-1.

Suitably if ethylene is the α-olefin in the rubber phase of the ICP, itmay be present in the range of from 25–70 weight percent, or at least 30and/or less than 65 percent based on the weight of the rubber phase. Therubber phase may be present in the ICP in the range of from 4–20 weightpercent, or at least 6 or 10 weight percent and/or less than 18 weightpercent, all based on the total weight of the ICP. The MFR of the ICPmay be in the range of from 15 to 60, or may be at least 20 and/or lessthan 50 or less than 40 dg/min. The ICP may be so-called reactor blends.

The ICP may also be a physical blend of polypropylene and one or moreelastomeric polymers of the ethylene α-olefin type, generally ethylenepropylene elastomeric polymers.

The ICP useful in embodiments of our invention may be prepared byconventional polymerization techniques such as a two-step gas phaseprocess using Ziegler-Natta catalysis. For example, see U.S. Pat. No.4,379,759 which is fully incorporated by reference. The ICPs ofembodiments of our invention are preferably produced in reactorsoperated in series, and the second polymerization, may be carried out inthe gas phase. The first polymerization, may be a liquid slurry orsolution polymerization process.

Metallocene catalyst systems may be used to produce the ICP compositionsuseful in embodiments of our invention. Current particularly suitablemetallocenes are those in the generic class of bridged, substitutedbis(cyclopentadienyl) metallocenes, specifically bridged, substitutedbis(indenyl) metallocenes known to produce high molecular weight, highmelting, highly isotactic propylene polymers. Generally speaking, thoseof the generic class disclosed in U.S. Pat. No. 5,770,753 (fullyincorporated herein by reference) should be suitable.

A description of semi-crystalline polypropylene polymers and reactorcopolymers can be found in “Polypropylene handbook”, E. P. Moore Editor,Carl Hanser Verlag, 1996.

The Hetero Phase Composition

The modifier component may be present in the hetero phase polymercomposition at ≧5, or ≧9, or ≧10, or ≧15, weight percent and/or ≦30, or≦25 weight percent, based on the total amounts of polymeric componentsin the hetero phase polymer composition.

The polypropylene component typically comprises ≧90 or ≦50 weightpercent of the hetero phase composition or 60–90 weight percent, or70–90 weight percent based on the total weight of the polymericcomponents.

The compatibilizer component may be present in the hetero phase polymercomposition in a compatibilizing amount. Those of skill in the art willunderstand that this indicates an amount sufficient for thecompatibilizer component not to form a separate phase and in any caseless than the amount of modifier component. A compatibilizing effect isevident if the average size of the dispersed phase regions is reduced incomparison with the same proportion of polypropylene component andmodifier component combined without compatibilizer. This can be assessedvisually as in U.S. Pat. No. 6,245,856, incorporated herein byreference. Additionally, a compatibilizing amount can be determined asthat amount that causes the impact strength, as determined by GardnerImpact at −29° C., to rise ≧15%, or ≧20%, or ≧25%, or ≧30% over/above ablend not containing such compatibilizer.

In other embodiments of our invention, the compatibilizer component maybe present in the hetero phase polymer composition at ≧0.1, or ≧0.3, or≧0.5, or ≧0.7, or ≧0.9, or ≧1, or ≦8, or ≦7, or ≦6, or ≦5 weightpercent, based on the total polymer weight in the hetero phase polymercomposition.

A variety of additives may be incorporated into the ICP for variouspurposes. Such additives include, for example, stabilizers,antioxidants, fillers, colorants, nucleating agents and mold releaseagents. Primary and secondary antioxidants include, for example,hindered phenols, hindered amines, and phosphates. Nucleating agentsinclude, for example, sodium benzoate and talc. Dispersing agents suchas Acrowax C can also be included. Slip agents include, for example,oleamide and erucamide. Catalyst deactivators are also commonly used,for example, calcium stearate, hydrotalcite, and calcium oxide.

Parameter Measurement

The crystallinity of ethylene based modifier component is convenientlymeasured by Differential Scanning Calorimetry (DSC), and is related tothe thermal history of the polymer. The modifier component may have asingle or multiple crystalline melting points above 23° C. Thetemperature of these melting peaks depends on the ethylene content ofthe polymer, on the ethylene sequence and compositional distribution,and on the thermal history of the polymer. These melting peaks typicallyrange from 30° C. up to 90° C. in polymers of very high ethylenecontent. When a polymer sample is melted (typically at 150° C. or above)and allowed to cool down, these crystalline melting peaks develop slowlywith time. Therefore, their relative quantification requires rigoroussample preparation protocols. We prefer therefore characterizing thecrystallinity of modifier component by their total crystallizationenthalpy measured by DSC after sample annealing at 150° C. or above.

Measurements

Molecular Weight and Polydispersity Index

Molecular weight distribution (MWD) is a measure of the range ofmolecular weights within a given polymer sample. It is well known thatthe breadth of the MWD can be characterized by the ratios of variousmolecular weight averages, such as the ratio of the weight averagemolecular weight to the number average molecular weight, Mw/Mn, or theratio of the Z-average molecular weight to the weight average molecularweight, Mz/Mw.

Mz, Mw and Mn can be measured using gel permeation chromatography (GPC),also known as size exclusion chromatography (SEC). This techniqueutilizes an instrument containing columns packed with porous beads, anelution solvent, and detector in order to separate polymer molecules ofdifferent sizes. In a typical measurement, the GPC instrument used is aWaters chromatograph equipped with ultrastyro gel columns operated at145° C. The elution solvent used is trichlorobenzene. The columns arecalibrated using sixteen polystyrene standards of precisely knownmolecular weights. A correlation of polystyrene retention volumeobtained from the standards, to the retention volume of the polymertested yields the polymer molecular weight.

Measurement

Physical Property Measurements:

Tensile Strength at Yield and Elongation at Yield:

Tensile strength at yield is measured according to ASTM D638, with acrosshead speed of 50.8 mm/min, and a gauge length of 50.8 mm, using anInstron machine. The elongation at yield is also measured according toASTM D638.

Flexural Modulus:

The flexural modulus is obtained according to ASTM D790A, with acrosshead speed of 1.27 mm/min (0.05 in/min), and a support span of 50.8mm, using an Instron machine.

Gardner Impact Strength and Failure Mode:

The Gardner impact strength was measured according ASTM D3029, Method G,Procedure GC, at −29° C. and on 90 mm diameter and 3.175 mm thicknessdisks. The failure mode is classified as shatter, brittle, and orductile, based on the nature of the failure type. For example, inshatter failure mode, the sample under test fractures into multiplepieces (often the number pieces can be 10–15) on impact by the fallingweight. In brittle failure, many radial cracks develop from around theimpact point, but the radial cracks do not propagate all the way to theouter periphery of the sample, and the pieces are held together. Inductile failure mode, only the sample portion that is impacted pushesout in an unsymmetrical manner, with a crack on one side, but rough andfibrillar surface is visible on the crack surface. The failure modes ofshatter-to-brittle, brittle-to-ductile, or a combination of the twodifferent types of failure modes in the sample. The failure mode ofbrittle-to-ductile which is in-between shatter and ductile, where theimpacted part shows radial cracks around the area of impact, even thoughthe piece is still intact. Even though the failure modes described aboveare based on human judgment, rather than a quantitative number from aninstrumental evaluation, the failure modes are very reproducible. Anindividual trained in the field can classify different materials usingthe Gardner impact test procedure very accurately.

Notched and Un-Notched Izod Impact Strength:

The room temperature and −30° C. notched izod impact strength ismeasured according to ASTM D256 test method. The impact strengthequipment is made by Empire Technologies Inc.

EXAMPLES

The thermoplastic olefin compounds of embodiments of the invention wereformulated either in a 30-mm ZSK twin screw extruder. Compounding in thetwin screw extruder was accomplished using an intense mixing screwelement. The batch size was 5000 gm. The temperature profile in thevarious extruder zones was ramped progressively from 170° C. to 210° C.The compounds discharged from the extruder were pelletized.

Standard test specimens conforming to ASTM specifications were preparedthrough injection molding on a 300-ton Van Dom press. The nozzle, frontand rear temperatures of the injection molding equipment were maintainedat 190° C. The mold temperature was kept constant at 27° C. The totalcycle time was 54 seconds and the injection pressure was 4 MPa. A familymold containing various ASTM specimen cavities was used.

Physical properties of the various samples are measured as described inTable 1.

TABLE 1 STANDARD TEST METHODS TEST METHOD Notched Izod Impact (J/m)ft-lb./inch ASTM D 256 Room Temperature −30° C. 1% Secant Modulus (MPa)psi ASTM D 790 A Tangent Modulus (MPa) psi Tensile Strength @ yield(MPa) psi ASTM D 638 Young's Modulus (MPa) psi Elongation @ yield/brk.(%) Melt Flow Rate (gm/10 min) ASTM D 1238, Condition L (230° C.)Condition E (190° C.) Gardner Impact @ −29° C. (dN · m) ASTM D 5420Geometry GC Rockwell Hardness ASTM D 785 Heat Distortion Temperature(HDT) ASTM D 648 @ (.45 MPa load) Instrumented Impact ExxonMobil Method(below) Crystalline Melting Point (abbreviated Tm) Differential ScanningCalorimetry (DSC). Heating and cooling rates were 10° C./minute. Tm isthe temperature at which a maximum occurs in the heat absorption curve.Glass Transition temperature (Tg) DSC, ASTM E-1356, at a heating rate of5° C./ minute) Density g/cm³ ASTM D-792

The ExxonMobil Test method is described in T. C. Yu “Impact Modificationof Polypropylenes with Exact Plastomers”, Soc. of Plastics Engineers,ANTEC, May 1994.

For this test method, high-speed puncture testing based on ASTM D-3763was used to study impact behavior. This test continuously measures theapplied force and time during the impact event. The electronicallycollected data points are next processed through a computer to providegraphic representation of both force and energy as a function ofdisplacement.

A drop-weight tester, Ceast Fractovis, was used to gather the data inTable 3. It consists of three main parts: clamp assembly, plungerassembly, and IBM PC based control unit. Two parallel rigid plates witha large opening to expose the test specimen form the clamp assembly.Both the top and bottom plates are of the same dimension. The plungerassembly consists of a steel rod with a removable hemispherical tip tohold the measuring strain gauge. It is located perpendicular to andcentered on the clamp hole. A control unit regulates the plunger testspeed, as well as records the load and displacement data. Similar to theconventional notched Izod testing, the test geometries need to becarefully defined because they are not precisely specified in the ASTMprocedure. A 20 mm diameter hemispherical striker and a 40 mm openingclamp were used for this study. The test speed was set at 4 m/sec. Forsub-ambient temperature testing, test specimens were chilled in afreezer for four hours at the test temperature. They were then stored ina liquid nitrogen cooled test chamber underneath the clamp assembly forfurther conditioning before testing.

A force-displacement graph may be generated for a ductile material.Integration of the force displacement curve, in turn, yields anenergy-displacement curve. This energy is reported in Table 3.Initially, a ductile material may behave as elastic solid in thatdeformation is proportional to the displacement. The initial slope ofthe generated graph is therefore a measure of the sample stiffness.After the elastic region, the sample starts to yield to the advancingplunger. At the yield point, the sample exerts its maximum resistance,the yield point is therefore the highest point on the force-displacementcurve. Afterwards, the high speed plunger initiates a crack in thesample and starts its downward penetration of the test specimen. Thesample then starts to draw to accommodate the advancing plunger. Finallythe plunger punctures through the test specimen; and, lastly, a smallamount of energy is needed to overcome the friction between the testplunger and the plastic sample. Because of the large extent of thissample drawing, the total energy is approximately twice the yieldenergy. A ductility index (DI) can be defined as:DI=[(Total Energy−Yield Energy)/Yield Energy]×100

The polypropylene resins selected for this study were impact copolymers,with melt flow rate in range of 20 to 35 dg/min. and total ethylenecontent in the polymer nominally in the range of 6 to 12 wt % and theethylene in the EP rubber phase was from 45 to 55 wt %. These arecommercially available under the trade name Escorene ®PP grades fromExxonMobil Chemical.

The very low density polyethylene (VLDPE) modifiers were copolymers ofethylene and hexene with density of 0.912 g/cm3 and melt index varyingfrom 3.5 to 12.5 dg/min. These are commercially available under thetrade name Exceed® (abbreviated as ECD) from ExxonMobil Chemical.

The compatibilizer component (labeled PC in Table 2) was a propyleneethylene copolymer with an ethylene content of 13 wt %. This polymer hasa Mooney Viscosity of 21.

TABLE 2 POLYMER CHARACTERISTICS PP PP ECD ECD 7715 E4 7414 411 330 PCMelt Flow Rate gm/10 35 20 — @ 230° C. min Melt Index @ gm/10 — — 3.512.5 — 190° C. min Mooney Viscosity MU — — — — 21 (1 + 4) 125° C.Density gm/cc 0.9 0.9 0.912 0.912 — Comonomer Type PP Impact CopolymerC6 C6 C2 Comonomer Wt. % Content

Table 3 shows thermoplastic olefin compounds containing a polymercompatibilizer in addition to the VLDPE impact modifier. The polymermodifier was ECD 411 (3.5 MI) that is dispersed in a 35 MFR PP impactcopolymer matrix. With the addition of the compatibilizer component(Examples 2 and 3) at low concentrations of 2% and 5% respectively,there was substantial improvement in room temperature (21° C.) notchedizod impact (RTNI) and notched izod at low temperature (−30° C.)toughness. Comparing Example 1 with 3, notched izod impact improves from97 J/m to no break. Failure mode at low temperature (−30° C.) for thecompounds containing the polymer compatibilizer was predominantlyductile. Examples 4 through 6 illustrate the effect of polymercompatibilizer (PC) at a higher polyethylene concentration of 20 wt %.The addition of PC substantially improves toughness. Additionalcomparative examples 7 to 9 contain formulations with 23 wt %polyethylene modifier content, demonstrating that at 23 wt %polyethylene, both room temperature (21° C.) toughness and lowtemperature (−30° C.) ductility was realized in the formulation (Example7). The PC addition (Examples 8 and 9) has little significant effect,since the formulations without the compatibilizer have good toughness.For completeness we have included in Table 3, a comparative example,example 10, from U.S. Pat. No. 6,245,856, showing that similar physicalproperties can be achieved with lower over all density of the modifiercomponent.

Although the present invention has been described in considerable detailwith reference to certain aspects and embodiments thereof, other aspectsand embodiments are possible. For example, while hetero phase polymercompositions have been exemplified, containing a polypropylenecomponent, an impact modifying component and a compatibilizingcomponent, other components and combinations are also contemplated.Therefore, the spirit and scope of the appended claims should not belimited to the description of the versions contained herein.

Certain features of the present invention are described in terms of aset of numerical upper limits and a set of numerical lower limits. Itshould be appreciated that ranges from any lower limit to any upperlimit are within the scope of the invention unless otherwise indicated.

All patents, test procedures, and other documents cited in thisapplication are fully incorporated by reference to the extent suchdisclosure is not inconsistent with this application and for alljurisdictions in which such incorporation is permitted.

TABLE 3 Example Ex 10 U.S. Pat. No. 1 2 3 4 5 6 7 8 9 6245856 PP 7715 E483 81 78 80 78 75 77 75 72 70* (polypropylene component) ECD 411(modifier 17 17 17 20 20 20 23 23 23 20* component) compatibilizer comp.0 2 5 0 2 5 0 2 5 10* Notched Izod Impact @ ° C. (J/m) 21.0 97.7 159.1NB 121.2 NB NB NB NB NB 524 −30.0 40.6 44.9 44.3 41.0 44.5 46.7 47.255.5 57.1 70 Instrumented Impact/ −30° C./24 km/h Total Energy (J) 7.78.2 7.9 8.0 8.0 8.2 7.7 7.9 7.9 Failure Type 4 D, 5 D 5 D 5 D 5 D 5 D 5D 5 D 5 D 1 DB Instrumented Impact/ −40° C./24 mph Total Energy (J) 4.43.5 3.6 5.1 4.8 6.0 6.9 6.6 6.5 Failure Type 4 BD, 5 BD 5 BD 5 BD, 2 DB,5 DB, 3 BD 1 D, 2 DB, 3 D, 2 DB 2 D, 2 DB, 2 D, 1 DB, 1 DB 1 D 2 BD 1 BD2 BD Flexural Modulus (MPa) @ 1.3 mm/min 1% Secant 1193 1069 952 10971021 834 993 924 821 779 Tangent 1214 1110 1007 1214 1076 841 1028 979883 814 Tensile Strength @ 51 mm/min @ Yield (MPa) 23.7 22.1 21.8 23.622.8 21.4 21.4 21.9 20.6 7.3 Young's Modulus (MPa) 1365 1177 1164 13881298 1080 1275 1165 6.5 Elongation (%) @ 51 mm/min Yield 7 9.1 11.5 8.110 13.3 10.5 12 14.8 18 Break 60 139 680 121 352 694 511 672 68.1 966MFR (g/10 min) 26.7 24.4 20.5 26.1 24.3 21.6 25 22.2 20.8 224.1 NB = NoBreak; D = Ductile, B = Brittle, BD = Brittle Ductile, DB = DuctileBrittle *note that the example from U.S. Pat. No. 6,245,856 which usesfor blend components a polypropylene homopolymer as the polypropylenecomponent, an ethylene propylene vinyl norbornene polymer with 57 wt %ethylene, 1.5 wt % VNB and the balance propylene, the compatibilizer isa polymer with a 33 Mooney viscosity and 12.4 wt % ethylene.

1. A polymer composition, comprising: a) a polypropylene component,comprising an isotactic or syndiotactic polypropylene polymer having amelting point (Tm) of 110° C. or more; b) a modifier component,comprising an ethylene α-olefin polymer, wherein the α-olefin isselected from the group consisting of C₄ to C₁₀ α-olefins; and c) acompatibilizer component, comprising a polymer that includes propylenesequences, a melting point (Tm) less than 105° C. and a heat of fusionless than 45 J/g.
 2. A polymer composition that includes a continuousphase and a dispersed phase, comprising: a) a polypropylene component,present in at least a portion of the continuous phase, comprising anisotactic or syndiotactic polypropylene polymer having a melting point(Tm) of 110° C. or more; b) a modifier component, present in at least aportion of the dispersed phase, comprising an ethylene α-olefin polymer,wherein the α-olefin is selected from the group consisting of C₄ to C₁₀α-olefins; and c) a compatibilizer component, present in either thecontinuous phase or the dispersed phase, or both, comprising a polymerhaving propylene sequences, a melting point (Tm) less than 105° C. and aheat of fusion less than 45 J/g.
 3. The polymer composition of claim 1,wherein the polymer composition does not break when subjected to aNotched Izod Impact Test in accordance with AS(TM) D 256@ 21° C.
 4. Thepolymer composition of claim 1, wherein the α-olefin of the modifiercomponent is butene.
 5. The polymer composition of claim 1, wherein theα-olefin of the modifier component is pentene.
 6. The polymercomposition of claim 1, wherein the α-olefin of the modifier componentis hexene.
 7. The polymer composition of claim 1, wherein the α-olefinof the modifier component is heptene.
 8. The polymer composition ofclaim 1, wherein the α-olefin of the modifier component is octene. 9.The polymer composition of claim 1, wherein the polypropylene componentis present in an amount of 70 to 90 weight percent of the composition.10. The polymer composition of claim 1, in which the compatibilizercomponent is present in an amount of 8 weight percent or less of thecomposition.
 11. The polymer composition of claim 1, wherein: a) thepolypropylene component is present in an amount of 70 to 90 weightpercent of the composition; b) the compatibilizer component is presentin an amount of 8 weight percent or less of the composition; and c) thepolymer composition does not break when subjected to a Notched IzodImpact Test in accordance with AS(TM) D 256@ 21° C.
 12. The polymercomposition of claim 1, wherein the modifier component is crosslinked.13. The polymer composition of claim 1, wherein the composition furthercomprises non-polymeric fillers and at least one compounding ingredient.14. The polymer composition of claim 1, wherein the composition is amultiphase thermoplastic vulcanizate in which the modifier component iscrosslinked and further comprises non-polymeric fillers and at least onecompounding ingredient.
 15. A polymer composition, comprising: a) apolypropylene component, present in said polymer composition as acontinuous phase, said polypropylene component having a melting point(Tm)≧110° C.; b) a modifier component, said modifier component being adispersed phase in said polymer composition, said modifier componentincluding at least 10 percent by weight of the total modifier componentbeing an ethylene α-olefin polymer in which the α-olefin is one or moreof butene-1, hexene-1, or octene-1; and c) a compatibilizer component,present in said polymer composition in a compatibilizing amount, saidcompatibilizer component having a Δ Hf<45 J/g, said compatibilizercomponent having propylene sequences co-crystallizable with thepolypropylene component of a).
 16. The polymer composition of claim 15,wherein said polypropylene component is an impact copolymer (ICP) ofpropylene and an α-olefin, said ICP having one or more of a (Tm)>115°C., a Δ Hf>60 J/g, or a total α-olefin content of <70 weight percent;said α-olefin being one of ethylene, butene-1,4methyl-1-pentene,hexene-1, octene-1, decene-1, ondecene-1, dodecene-1 or combinationsthere of; and wherein said polypropylene component is one of isotactic,syndiotactic, atactic, or combinations thereof.
 17. The polymercomposition of claim 16, wherein said polypropylene component has one ormore of a (Tm)>125° C., a Δ Hf of >80 J/g, or an α-olefin content of >2wt. % or <50 wt. %, based on the total weight of said polypropylenecomponent, and wherein said α-olefin of said polypropylene component isone or more of ethylene, butene-1,4methyl-1-pentene, hexene-1, octene-1.18. The polymer composition claim 16, wherein said polypropylenecomponent has one or more of a (Tm)>130° C., a Δ Hf of >85 J/g; or anα-olefin content of >2 wt. % or <40 wt. %, based on the total weight ofsaid polypropylene component, and wherein said α-olefin of saidpolypropylene component is one or more of ethylene, butene-1, hexene-1,and octene-1.
 19. The polymer composition of claim 15, wherein saidpolypropylene component has one or more of a (Tm)>135° C., a Δ Hf of >90J/g; or an α-olefin content of >2 wt. % or <30 wt. %, based on the totalweight of said polymer composition.
 20. The polymer composition of claim16, wherein said polypropylene component has one or more of a (Tm)>140°C., a Δ Hf of >95 J/g; or an α-olefin content of >2 wt. % or <25 wt. %,based on the total weight of said polypropylene component, saidpolypropylene component having a molecular weight in the range of from10,000 to 5,000,000, said polypropylene component having a melt flowrate (MFR), in the range of 15–60 g/10 min; said ICP including ahomopolymer polypropylene and rubber, said rubber being present in saidICP in the range of from 4–20 wt. %, based on the total weight of saidICP, said rubber having an α-olefin content of 25–70 weight %.
 21. Thepolymer composition of claim 15, wherein said modifier component is asingle polymer or a blend of two or more ethylene α-olefin polymers,said α-olefin being one of butene-1, 4-methyl-1-pentene, hexene-1,octene-1, decene-1, ondecene-1, dodecene-1 or combinations thereof, saidα-olefin or α-olefins present in said ethylene α-olefin polymer orpolymers <20 mole %, in each if two or more are present, said modifiercomponent being substantially devoid of propylene crystallinity.
 22. Thepolymer composition of claim 15 wherein said compatibilizer componentand said polypropylene component have substantially the samestereoregularity, chosen from one of isotactic, syndiotactic, atactic,or combinations there of; said compatibilizer component being apropylene α-olefin polymer having one or more α-olefin comonomerspresent in said compatibilizer component, said α-olefins selected fromone or more of ethylene or an α-olefin having 4–12 carbon atoms.
 23. Thepolymer composition of claim 15 wherein said compatibilizer componenthas a crystallizable portion and an amorphous portion, said amorphousportion being the result of one of stereo error introduced by a catalystor by the amount and nature of a comonomer.
 24. The polymer compositionof claim 15 wherein said compatibilizer component is a polymer ofpropylene and one or more of ethylene, butene-1, 4-methyl-1-pentene,hexene-1, octene-1, and decene-1.
 25. The polymer composition of claim15, wherein said compatibilizer component is a polymer of propylene andone or more of ethylene, butene-1, hexene-1, or octene-1; wherein saidcompatibilizer component has a crystallinity defined by a melting point(Tm)<105° C., and/or a Δ Hf<35 J/g, and/or a Mooney viscosity ML(1+4)@125° C.<100, said compatibilizer component having a narrowcompositional distribution, such that >75 wt. % of the compatibilizercomponent may be isolated in a thermal fractionation, in 2 adjacentsoluble fractions, such that each fraction differs <20% from the averageweight present α-olefin of the total compatibilizer component; whereinsaid polypropylene component is present in said polymer composition inthe range of from 70–90 wt. %; said modifier component being present insaid polymer composition in the range of from 10–25 wt. %; and saidcompatibilizer component being present in said polymer composition inthe range of from 0.1–8 wt. %; said weight percents of a), b) and c),being based on the total polymer weight of said polymer composition. 26.The polymer composition of claim 15, wherein said compatibilizercomponent has a crystallinity defined by a melting point (Tm)<100° C.,and/or a Δ Hf<25 J/g, and/or a Mooney viscosity ML (1+4)@125° C.<75;wherein said polypropylene component is present in said polymercomposition in the range of from 80–90 wt. % wherein; said modifiercomponent is present in said polymer composition in the range of from15–22 wt. %; and said compatibilizer component is present in saidpolymer composition in the range of from 0.1–5 wt. %; and wherein saidweight percents of a), b) and c) are based on the total polymer weightof the polymer composition.
 27. The polymer composition 1, wherein saidethylene α-olefin polymer is substantially free of propylenecrystallinity.
 28. The polymer composition 2, wherein said ethyleneα-olefin polymer is substantially free of propylene crystallinity. 29.The polymer composition of claim 15, wherein said ethylene α-olefinpolymer is substantially free of propylene crystallinity.